Water soluble corrosion inhibitors

Abstract

This invention is a method for inhibiting corrosion in metallic flow lines containing hydrocarbon and/or aqueous fluids comprising adding to the fluid contained in the flow line a corrosion inhibiting amount of a water-soluble ampholytic substituted imidazoline having the formula: <IMAGE> wherein R1 comprises a radical selected from the group consisting of hydrogen, alkyl, and aryl groups having 6 to 30 carbons; R2 comprises a radical selected from the group consisting of polyalkylene polyamines having from 2 to 16 carbon atoms, NH2, N(R4)2, OH and SH; R3 is a radical selected from the group consisting of carboxylate, carbonate, sulfite, sulfate, phosphite, and phosphate; n is a number from 1 to 10; and, R4 comprises a branched or linear alkyl chain having a length of 1 to 8.

What is claimed is: 
     
       1. A method for inhibiting corrosion in metallic flow lines comprising adding to the fluid contained in the flow line a corrosion inhibiting amount of a water-soluble ampholytic substituted imidazoline having the formula: ##STR6## wherein R 1  comprises radical selected from the group consisting of hydrogen, alkyl and aryl groups having 6 to 30 carbons; R 2  comprises radical selected from the group consisting of polyalkylene polyamines having from 2 to 16 carbon atoms, NH 2 , N(R 4 ) 2 , OH and SH, R 3  is a radical selected from the group consisting of carboxylate, carbonate, sulfite, sulfate, phosphite and phosphate; n is a number from 1 to 10; and, R 4  comprises a branched or linear alkyl chain having a length of 1 to 8 carbons. 
     
     
       2. The method of claim 1, wherein the imidazoline is added to the flow line continuously to maintain a corrosion inhibiting dose of from 0.01 to 5,000 parts per million. 
     
     
       3. The method of claim 2, wherein the imidazoline is added to the flow line continuously to maintain a corrosion inhibiting dose of from 0.1 to 500 parts per million. 
     
     
       4. The method of claim 3, wherein the imidazoline is added to the flow line continuously to maintain a corrosion inhibiting dose of from 1 to 250 parts per million. 
     
     
       5. The method of claim 1, wherein the flow line is comprised of mild steel. 
     
     
       6. The method of claim 1, wherein R 1  comprises an alkyl group having 10 to 26 carbons. 
     
     
       7. The method of claim 6, wherein R 1  comprises an alkyl group having 14 to 22 carbons. 
     
     
       8. The method of claim 1, wherein R 1  comprises an aryl group selected from the group comprising phenyls, tolyls and dodecyl benzene. 
     
     
       9. The method of claim 1, wherein the flow rate of fluid through the flow line is from 0 to 65 feet per second. 
     
     
       10. The method of claim 9, wherein the flow rate of fluid through the flow line is from 0 to 40 feet per second. 
     
     
       11. The method of claim 10, wherein the flow rate of fluid through the flow line is from 0 to 35 feet per second. 
     
     
       12. A corrosion inhibitor composition for metallic flow lines, comprising: a) an ampholytic, water-soluble substituted imidazoline having the formula: ##STR7##  wherein R 1  comprises a radical selected from the group consisting of hydrogen, alkyl and aryl groups, R 2  comprises a radical selected from the group consisting of polyethylene polyamines, NH 2 , N(R 4 ) 2 , OH and SH; R 3  is a radical selected from the group consisting of carboxylate, carbonate, sulfite, sulfate, phosphite, and phosphate and; n is a number from 1 to 10; and, R 4  comprises a branched or linear alkyl chain having a length of 1 to 8 carbons;   b) a water soluble surfactant; and   c) water.   
     
     
       13. The composition of claim 12, wherein the surfactant is selected from the group comprising an ethoxylated alkyl amine or an ethoxylated nonyl phenol. 
     
     
       14. The composition of claim 12, further including a pour point depressant selected from the group comprising alcohols and glycols. 
     
     
       15. The composition of claim 12, further including a co-inhibitor selected from the group comprising amides, quaternized amines and amide amine salts. 
     
     
       16. The composition of claim 12, further including a filming agent selected from the group comprising agent p-toluene sulfonic acid and dodecyl benzene sulfonic acid. 
     
     
       17. A method for inhibiting corrosion in metallic flow lines comprising adding to the fluid contained in the flow line a) a corrosion inhibiting amount of a water-soluble ampholytic substituted imidazoline having the formula: ##STR8##  wherein R 1  comprises a radical selected from the group consisting of hydrogen, an alkyl group having 14 to 22 carbons, an aryl group selected from the group comprising phenyls, tolyls and dodecyl benzene; R 2  comprises a radical selected from the group consisting of polyalkylene polyamines having from 2 to 16 carbon atoms, NH 2 , N(R 4 ) 2 , OH and SH, R 3  is a radical selected from the group consisting of carboxylate, carbonate, sulfite, sulfate, phosphite and phosphate; n is a number from 1 to 10; and, R 4  comprises a branched or linear alkyl chain having a length of 1 to 8 carbons; and wherein the imidazoline is added to the flow line continuously to maintain a corrosion inhibiting dose of from 1 to 250 parts per million.   
     
     
       18. A corrosion inhibitor composition for metallic flow lines, comprising: a) an ampholytic, water-soluble substituted imidazoline having the formula: ##STR9##  wherein R 1  comprises a radical selected from the group consisting of hydrogen, alkyl and aryl groups, R 2  comprises a radical selected from the group consisting of polyethylene polyamines, NH 2 , N(R 4 ) 2 , OH and SH; R 3  is a radical selected from the group consisting of carboxylate, carbonate, sulfite, sulfate, phosphite and phosphate; and n is a number from 1 to 10; and, R 4  comprises a branched or linear alkyl chain having a length of 1 to 8;   b) a water-soluble surfactant selected from the group comprising an ethoxylated alkyl amine or an ethoxylated nonyl phenol;   c) a pour point depressant selected from the group comprising alcohols and glycols;   d) a co-inhibitor selected from the group comprising amides, quaternized amines and amide amine salts;   e) a filming agent selected from the group comprising agent p-toluene sulfonic acid and dodecyl benzene sulfonic acid;   f) water.